Substitution of plastic compositions for structural articles formed from non-plastic materials may meet objections regarding relatively low physical properties of the substitute plastic composition. Manufacturers often blend the plastic composition with other resins and additives to improve the physical properties. But, the blends of resins and additives may decrease the recyclability of the plastic composition.
In one example of a structural article suitable for material substitution, railroad ties support relatively great weights of railroad locomotives and their attached train cars with their contents. As the trains pass over railroad rails supported on railroad ties, the ties experience substantial vibration, in addition to the compressive force of the weight. When the ties are not in use, they are still subjected to harsh environment extremes of temperature, ultraviolet light, and moisture. The degradation of wooden railroad ties through this exposure to the environment requires that the ties must be replaced frequently in order to continue to perform their primary function of supporting the weight of the train. The wood used to make conventional railroad ties is increasingly becoming more expensive. Wooden railroad ties are heavy making the job of replacing them difficult.
Panels, especially load-bearing panels are used in many applications. For example, vehicle manufacturers attempt to reduce the weight of the vehicles in order to enhance the fuel economy of the vehicle. Often, the reduction in weight compromises component part strength as wall thickness of blowmolded, thermoformed, rotocasted, and rotomolded components is reduced in order to a component reduce weight. For example, load floor systems have a relatively long span that is unsupported across the inside of the vehicle, in order to provide load-bearing characteristics. At the same time, plastic processors are consolidating components in load floor systems in order to reduce further the load floor weight and the assembly labor costs. In certain instances, plastic processors have incorporated glass fiber reinforcements into the plastic material used to make load floors. But, these reinforcements and fillings may also render the load floor system component brittle and not suitable for all the characteristics of load floor systems designs. Recently, plastic processors have incorporated cone tack-offs to provide stiffening for vehicle load floor systems in order to compensate for component part strength reduction. But, cone tack-offs produce witness marks that damage aesthetic properties of a show surface. It is desirable to consolidate components in load floor systems while at the same time eliminating cone tack-offs.
In at least one embodiment, a panel system includes a first panel having a periphery. The panel includes a first plastic layer having a periphery and a second plastic layer opposed and spaced apart from the first layer. The second layer also has a periphery. The first and second layers define a first cavity therebetween. A first in-situ foam core is disposed in the cavity and has a thermal bond to the first and second plastic layers. The panel is capable of supporting 0.1 to 0.5 lbf/in2.
Vehicle manufacturers attempt to reduce the weight of the vehicles in order to enhance the fuel economy of the vehicle. Often the reduction in weight compromises the strength of component parts. Recently, regulations, such as ECE17 and Federal Motor Vehicle Safety Standards (FMVSS), such as FMVSS202A, have mandated a stiffer component structure for vehicle seats and greater energy absorption for associated seat headrests.
Recent components such as seat backs comprising a plastic blend of polycarbonate and acrylonitrile butadiene styrene (PC/ABS) have increased the cost of seat backs as well as increased the weight of the blowmolded polyethylene seat backs that they replaced. In other situations, headrests formed of polyurethanes foam failed the vertical height volumetric compression test as well as the deformation retention test.